No reincarnation, no transmigration, no reborn. It's just that MC stumbled upon a romance novel which turns out to be a prophecy written by the prince's wet nurse (also the prime minister's wife cmiiw and currently the workaholic MC's employee).
The MC herself is so smart, and straightforward and sassy and not silently scheming which I found pretty refreshing. Even his majesty the king admit that. Until to the point where he will find a way for her to marry his son and get into the royal family.
Imho, I think it is the best to add a reverseharem tag. Because as I read so far, there has been no progress on MC romance with any male, maybe the prince, but she also got a bunch of male admirers surrounding her.
A male character was introduced in the next arc, he found MC interesting and different, then he joined her circle of friends. I believe that is the cycle of a reverse harem.